Carter Lake

Carter Lake is a 315 acre oxbow lake along the Missouri River between Nebraska and Iowa. Elevated phosphorus levels resulted in cyanobacteria (a.k.a.blue-green algae) blooms and subsequent microcystin algae toxin production. From 2005-2008, beach warnings were posted for 21 of the 80 weeks of peak summer recreation. A whole lake alum treatment was completed in May 2010, a success story jointly published by Nebraska and Iowa officials can be downloaded below.

The alum treatment resulted in the following changes:

Total phosphorus declines of 72%

Total nitrogen declines of 52%

Algae toxins are virtually non detectable and beaches have not been closed since the treatment

Water clarity has improved

Newly stocked game fish have flourished

The lake is proposed to be removed from USEPA’s Clean Water Act section 303(d) list for impaired waters due to algae toxin